Suction and discharge valves generally present the biggest maintenance concern on reciprocating compressors. Faulty valves substantially decrease compressor efficiency, among other problems. Conventional compressor monitoring systems rely heavily on analysis of pressure-volume (PV) curves to evaluate operation and determine status of suction and discharge valves in large reciprocating compressors. Such conventional compressor monitoring systems also monitor crosshead vibration or utilize portable ultrasonic sensors to evaluate valve health. While such configurations and techniques are useful locating an operational failure of a general region, such as an entire cylinder, they are unable to pinpoint the specific valves responsible for the problem. Replacing all valves in a region is costly, and downtime due to unplanned maintenance following a valve failure only adds to this cost.
More recently, a non-invasive velocity, acceleration, and temperature sensor designed to be mounted directly on a compressor valve cap and sense vibrations in the range of 2 Hz to 1500 Hz has been introduced. This low frequency range is not suitable for stress wave analysis and contains enormous normal vibration machinery and process operation and background noise information, all of which may be overwhelming compared to important signal information indicative of valve failure.
It is with respect to these and other considerations that the present invention was conceived.